The present invention pertains generally to the production of an encapsulated window assembly, and more particularly to a method of and apparatus for molding a suitable film onto a surface of the encapsulating polymer molding during formation of the molding by the reaction injection molding process.
For many years automotive vehicle windows were installed utilizing suitable mechanical fasteners such as metal clips, with adhesive sealants applied around the margin of edges of the glass unit, and exterior decorative trim strips disposed to cover the junction between the original edges of the glass sheet and the adjacent portions of the vehicle body and present a pleasing appearance. Assembly procedures for such window structures required a great deal of labor inasmuch as it was necessary to manually assemble the individual components as the vehicle moved along the assembly line. As labor rates increased, the cost thus became increasingly burdensome.
In an effort to improve the seal around the window, as well as to reduce the amount of labor required for installation, unitary window assemblies such as those illustrated in U.S. Pat. No. 4,072,340 were developed. Such assemblies comprise a sheet of glass or a laminated glass unit surrounded by a preformed casing or gasket of molded material such as polyvinyl chloride for insertion in an adjacent frame. The casing or gasket extends between the frame and the peripheral edge of the window to secure the window within the opening. Fasteners are provided on the frame so that the entire assembly can be guided into location within the opening in the vehicle body as a unit. Such window structures effectively reduce the time required to mount the window assembly in the vehicle, but they are still relatively costly since the individual components comprising each window assembly must be manually assembled.
More recently as disclosed, for example, in U.S. Pat. No. 4,561,625, so-called encapsulated automotive glazing units have been developed wherein a gasket is formed around at least a predetermined portion of a glazing unit of transparent material such as glass. The glazing unit may comprise a single sheet of glass as used in automotive side lights or backlights, or a laminated unit as employed for windshields. Such gaskets are generally formed by curing a polymeric gasket forming material in situ on the glazing unit to encapsulate the marginal peripheral edge portion of the unit. The gasket is typically formed by a reaction injection molding, or so-called RIM encapsulating process. Fabrication of such encapsulated glazing units is disclosed, in the aforementioned U.S. Pat. No. 4,561,625, the disclosure of which is incorporated herein by reference. The encapsulated unit can then be readily mounted in an appropriately shaped opening in a vehicle body without further manual assembly of additional components.
Encapsulated units require a minimum of manual labor in their fabrication and installation. The material utilized in forming the gasket around the unit by the reaction injection molding process is generally a flowable polymeric material which can be cured in situ on the glass sheet. Such materials may be susceptible to degradation upon extended exposure to the elements, particularly the effects of ultraviolet radiation resulting from prolonged exposure to sunlight. In order to minimize the possible deleterious effects of such exposure, it has been deemed advisable to provide the surfaces of the molding which are to be exposed to the elements, particularly those which will be exposed to sunlight, with a protective coating. To that end, exposed surfaces of encapsulated units have heretofore been coated with a weather-stable paint which protects the polymer material from the effects of ultraviolet radiation. Such painting of the surfaces of the encapsulated parts following molding of the gaskets involves substantial costs in labor, materials and equipment. Thus, there has been a recognized need for a system to replace the post-painting of encapsulated parts.